Automatic air valve control apparatus

ABSTRACT

An apparatus particularly for controlling the amount of air supplied to an air-lift pump used for pumping return sludge from a clarifier section to an aeration section of a sewage and waste treatment plant. A weir is arranged for diverting a portion of a flow from a flow path created by the air-lift pump. This diverted flow portion is fed to an arrangement including a pair of troughs for weighing the diverted flow portion. One arm of a balance beam is connected to one of the troughs and to an air control valve for regulating the air supplied to the air-lift pump as a function of the weight of the diverted flow portion. The trough connected to the regulating arrangement is connected to the other trough at an end spaced from its connection to the regulating arrangement by a device for inversely duplicating in the trough a displacement of the other trough, resulting in the spaced end of the trough being displaced by the other trough and the rate of flow in the trough being thus varied. As a, for example, heavier sludge or other material flows through the trough and into the other trough, the material receiving end of the trough will be raised resulting in the trough holding less material, and a counterweight on the other balance beam arm will move the end of the trough connected to the balance beam upwardly and increase the supply of air to the air-lift pump. A lighter sludge or other material flowing into the other trough reverses this procedure.

United States Patent [1 1 Hall [ AUTOMATIC AIR VALVE CONTROL APPARATUS[76] Inventor: Ellis C. Hall, Rt. 2, PO. Box 107,

Gautier, Miss. 37553 22 Filed: Apr. 17,1972

21 Appl. No.: 244,763

Primary Examiner-Carlton R. Croyle Assistant ExaminerRichard E. GluckAttorneyHarvey B. Jacobson [57] ABSTRACT An apparatus particularly forcontrolling the amount 1 Dec. 4, 1973 of air supplied to an air-liftpump used for pumping return sludge from a clarifier section to anaeration section of a sewage and waste treatment plant. A weir isarranged for diverting a portion of a flow from a flow path created bythe air-lift pump. This diverted flow portion is fed to an arrangementincluding a pair of troughs for weighing the diverted flow portion. Onearm of a balance beam is connected to one of the troughs and to an aircontrol valve for regulating the air supplied to the air-lift pump as afunction of the weight of the diverted flow portion. The troughconnected to the regulating arrangement is connected to the other troughat an end spaced from its connection to the regulating arrangement by adevice for inversely duplicating in the trough a displacement of theother trough, resulting in the spaced end of the trough being displacedby the other trough and the rate of flow in the trough being thusvaried. As a, for example, heavier sludge or other material flowsthrough the trough and into the other trough, the material receiving endof the trough will be raised resulting in the trough holding lessmaterial, and a counterweight on the other balance beam arm will movethe end of the trough connected to the balance beam upwardly andincrease the supply of air to the air-lift pump. A lighter sludge orother material flowing into the other trough reverses this procedure.

6 Claims, 6 Drawing Figures i From Clan fer Serif/m1 AUTOMATIC AIR VALVECONTROL APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention-This invention relates in general to an apparatus for regulating theimpetus to a flow in a flow path as a function of a quantitativemeasurement of the flow. In particular, this invention relates to suchan apparatus for use in controlling the amount of air supplied to anairlift pump used for pumping return sludge from a clarifier section toan aeration section of a sewage and waste treatment plant.

2. Description of the Prior Art One of the most important factors inoperating sewage and waste treatment plants at peak efficiency relatesto the controlof the air supply to the return sludge air-lift pump. Thisreturn sludge air-lift pump returns sludge from the bottom of aclarifier section of the plant to the aeration section thereof forrecycling. In a small treatment plant, the sludge must be pumpedcontinuously and at a fixed volume to maintain an acceptable culture inthe aeration section and a clear water zone in the clarifier section forfinal effluence. Efficient performance of this operation is dependentupon proper control of the air supply by means of an air valveincorporated in the air-lift apparatus. Proper air supply control is avery critical problem in practically all sewage and waste treatmentplants. The majority of these problems relate to the variation in loadbetween peak and non-peak operating hours, the former being generallyfrom 6:00 A.M. to 12:00 P.M. and the latter from 12:00 P.M. to 6:00 A.M.A large volume of sludge tends to accumulate in the clarifier sectionduring the peak operating hours. The opposite is true during nonpeakoperating hours. Accordingly, in order to maintain an acceptableaeration culture at a constant level for the clear water zone of theclarifier, a larger or smaller volume of sludge must be returned tothe'aeration section during respective peak and non-peak hours. Thepresent practice is to transfer sludge from the clarifier to theaeration section by an air-lift pump operating on a fixed manual airsupply valve setting usually determined by computing an average betweenthe peak and non-peak operating loads, since the constant manualattention that would be required for operation in each situation isimpractical for the average plant.

It is known to control a flow, as shown in, for example, U. S. Pat. Nos.1,155,473; 1,406,323, and 1,646,753, by the use of weight-responsiveregulating devices. However, none of these known weightresponsiveregulating devices are suitable for use in controlling the air supply toan air-lift pump such as used in sewage and waste treatment plants.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide an apparatus for automatically regulating the impetus to a fiowin a flow path as a function of a quantitative measurement of the flow.

It is a specific object of the present invention to provide an apparatusfor controlling the amount of air supplied to an air-lift pump used forpumping return sludge from a clarifier section to an aeration section ofa sewage and waste treatment plant. I

These and other objects are achieved according to the present inventionby providing means for making a quantitative measurement of a flow in aflow path, and means for regulating the impetus to the flow in the flowpath as a function of the measurement made by the measuring means.

According to a preferred embodiment of the present invention, themeasuring means continuously makes quantitative measurements of a flowportion diverted from the flow path.

The measuring means may have a displaceably mounted trough defining aflow channel connected to the regulating means and arranged forreceiving the diverted flow portion. A further trough is arranged toreceive from the trough at least a part of the diverted portion. Thisfurther trough is displaceably mounted at the ends thereof, and isconnected to the trough at one of its ends for displacing the trough.The trough is connected to the regulating means at a one end and to thefurther trough at the other end. The troughs are preferably connectedtogether by a means for inversely duplicating in the trough adisplacement of the further trough. This arrangement results in only theother end of the trough being displaced by the further trough, and therate of flow in the trough being varied.

The regulating means advantageously has a pivotally mounted balance beamhaving a counterweight mounted on a one arm thereof and the other armconnected to the trough for movement thereby.

In a preferred application of the apparatus claimed in the presentinvention, the flow path is defined by an airlift pump, and the meansfor regulating has an air control valve connected to its other arm foractuation thereby.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary, sideelevational view showing an apparatus according to the presentinvention.

FIG. 2 is a top plan view showing the apparatus of FIG. 1.

FIG. 3 is a fragmentary, end elevational view showing the apparatus ofFIGS. 1 and 2.

FIG. 4 is a sectional view taken generally along the line 4-4 of FIG. 1.

FIG. 5 is a sectional view taken generally along the line 5-5 of FIG. 1.

FIG. 6 is a fragmentary, side elevational view, partly in section,showing a detail of an air supply control assembly for use with anapparatus according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 of the drawingshow an apparatus according to the present invention associated with anairlift pump 10. Although a central air-pipe system is shown in thedrawings, it is to be understood that any known, suitable air-lift pumpsystem may be employed. Further, the control apparatus according to thepresent invention may be used with other conveying devices, such astroughed belts and the like. Pump 10 may be used for pumping returnsludge from a clarifier section to an aeration section of a sewage andwaste treatment plant. A weir 12 is arranged for receiving the returnsludge, other polluted fluid, or other material from pump 10, and fordiverting a portion of the material from the flow of material created bypump 10. This is shown by the flow arrows in FIG. 1. The undivertedportion of the flow passes through an opening 13 and falls by gravityinto the aerator. An arrangement 14 is provided for continuously makingquantitative measurements of the diverted flow portion. This arrangement 14 is connected to an arrangement 16 for regulating the airsupplied to pump as a function of the measurements by arrangement 14.The flow is passed from pump 10 to arrangement 14 by means of a trough18 provided with weir l2 and opening 13, and by a trough 19.

Arrangement 14 includes a trough 20 arranged for receiving the divertedflow portion from trough 19 via a chute 21 provided in trough 19. Trough19 also is provided with a sliding gate 22 which permits the volume ofsludge or other material conveyed through trough 20 to be adjusted.Trough 20 is displaceably mounted and defines a flow channel for thediverted flow portion. Arrangement 16 has a balance beam 23 pivotallymounted on a support 24 as by pin 26 and having a counterweight 28adjustably mounted on a one arm 30 thereof. the other arm 32 isconnected to trough 20 by adjustable rod 34 and a bracket 36. Thisconnection causes balance beam 23 to be moved by trough 20. Support 24,which may be a pair of upstanding members as can be seen in FIG. 2 ofthe drawings, is mounted in a known manner on a support frame 37. Alsohaving one end connected to frame 37 is a damper 38. The other end ofdamper 38 is connected to arm 30 of balance beam 23. Damper 38 may be ofconven tional construction and employ a fluid medium such as oil toachieve the dash-pot or damping effect. An air control valve assembly 40is arranged on frame 37 adjacent arm 32 of beam 23. A line 42 suppliesair to assembly 40 from a suitable, known source (not shown), and a line43 conveys the air to pump 10. A valve 44 is arranged in line 42 forproviding an adjustment and an on-off control for assembly 40.

Arrangement 14 also has a trough 46 arranged to receive from trough 20at least a part of the diverted flow portion. This trough 46 isdisplaceably mounted to frame 37 at one end, the right end as seen inFIG. 1 of the drawings, as by an adjustably mounted rod 48 and a bracket50. A spring 52 is arranged at one end of rod 48 for permittingdisplacement of rod 48, and is adjustably attached in a known manner toa bracket 54 which is in turn mounted on frame 37. Trough 20 is providedwith a weir 56 and an oepning 58. The part of the diverted flow portionwhich flows over weir 56 passes through the aeration tank (not shown),and only the part that flows through opening 58 passes to trough 46.

Troughs 20, 46 are connected together by an arrangement 60 for inverselyduplicating in trough 20 a displacement of trough 46. Arrangement 60 ismounted on a bracket 62 which in turn is mounted on a displaceablesupport assembly 64. To the top of assembly 64 is mounted a damper 66.

As can best be seen from FIGS. 3 to 5 of the drawings, assembly 64 has apair of longitudinally extending supports 68. These supports .68 mountbracket 62 and arrangement 60 to frame 37. A rod 70 is arranged betweensupports 68 and is connected at its lower end to trough 46 by means of abracket 72. The other end of rod 70 is connected to damper 66.

Arrangement 60 includes a plurality of pulleys 74, four being shown inthe illustrated embodiment, mounted in a known manner for rotation onsupport member 76. Support members 76 are in turn connected to bracket62. A pair of cables 78 are arranged about pairs of pulleys 74 on eachsupport member 76. The ends of cable 78 are attached to troughs 20, 46.By this arrangement, a, for example, downward displacement of trough 46will pull trough 20 upwardly, and an upward displacement of trough 46will permit trough 20 to lower under the force of gravity.

Damper 66 is provided with frame 80 to which is connected in a knownmanner and end of springs 82 and one portion of a dash-pot or fluiddamper 84. The other end of springs 82 and damper 84 is connected to aplate 86 which is in turn connected to rod 70. Thus, damper 66 acts todampen the movements of trough 46.

The arrangement of trough 20 wherein it is connected to arm 32 at oneend and to trough 46 atthe other end results in only the end connectedto trough 46 being displaced by trough 46 and the rate of flow in trough20 being thus varied.

FIG. 6 of the drawings shows in detail a possible construction for valveassembly 40. This embodiment has a valve 88 with a valve element 90biased by a spring 92 toward a valve seat 94. Element 90 has a pin 96projecting therefrom and passing through a bore defined in valve housing98. A rocker is pivotally mounted to housing 98 as by a pin 102, and isconnected to arm 32 as by a link 104. The other end of rocker 100 isprovided with a bearing surface 106 which contacts pin 96. As can bereadily understood from FIGS. 1 and 6 of the drawings, a movement ofbeam 23 will cause a proportional movement of rocker 100 resulting in achange of position of element 90 with relation to seat 94. In thismanner, the amount of air supplied to pump 10 may be adjusted as afunction of the weightof the material being pumped.

To operate the particular embodiment shown in the drawings, slide gate22 is closed and valve 44 is open to start pump 10. A large volume ofsludge or other material pumped by pump 10 will spill over the longsloping side of weir 12 into trough 19. The diverted portion passinginto trough 19 will flow through chute 21 and into trough 20. The rateof sludge or other material will pull down arm 32 of beam 23, andelement 90 of valve 88 will move toward seat 94. The movement of element90 will be slow because of damper 38 on arm 30 of beam 23. When valve 88closes to a point where the air-lift pump 10 pumps just enough sludge orother material so that a small volume will spill over the side of weirl2 and flow through troughs 20 and 46, the weight of that sludge orother material will balance the weight of counterweight 28. Pump 10 willthen continue to pump the same volume of sludge or the like. To changethe volume of sludge or the like being pumped, slide gate 22 is openeduntil the desired volume is being pumped. As a matter of normaloperation, the sludge or the like varies in thickness and weight. Tocompensate for such variations, the sludge flows through trough 46 andat least a part thereof passes out of opening 58 and into trough 46. Ifthe sludge flowing through trough 20 and into trough 46 becomes heavier,the receiving end of trough 46 will pull down on rod 48 causing adisplacement of spring 52. Trough 46 will thus fill to a weightsufficient to pull down the other end of trough 46. When the other endof trough 46 is displaced downwardly it will cause the adjacent end oftrough 20 to be displaced upwardly, resulting in trough 20 holding lessfluid. This inverse displacement will cause counterweight 28 on beam 23to move downwardly and cause valve 88 to open resulting in more sludgeor the like being pumped by pump 10. The sludge or the like in trough 46will discharge as trough 46 moves downwardly until the sludge in trough46 equals the weight of the sludge or the like in trough 20. Theopposite sequence of events occurs when a lighter sludge or the likeflows through trough 20 and into trough 46, ultimately causing valve 88to restrict and effecting a reduction in the amount of sludge or thelike being pumped. By proper selection and adjustment of the variouselements, including the position of gate 22, in view of experience witha particular plant and in conjunction with routine sewage and wastetreatment plant maintenance, any small plant facility provided withapparatus according to the present invention can be made to operate atpeak efficiency.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention.

What is claimed as new is as follows:

1. An apparatus, comprising, in combination:

a. means for making a quantitative measurement of a flow in a flow path,the measuring means continuously making quantitative measurements of aflow portion diverted from the flow path, and including a displaceablymounted trough defining a flow channel connected to the regulating meansand arranged for receiving the diverted flow portion, and a furthertrough arranged to receive from said trough at least a part of thediverted portion, said further trough being displaceably mounted at theends thereof and connected to said trough at one end for displacingsame; and

b. means for regulating the impetus to the flow in the flow path as afunction of the measurement made by the measuring means.

2. A structure as defined in claim 1, wherein the troughs are connectedtogether by a means for inversely duplicating in said trough adisplacement of said further trough.

3. A structure as defined in claim 2, wherein said trough is connectedto said regulating means at a one end and to said further trough at theother end, this arrangement resulting in only the other end of saidtrough being displaced by said further trough and the rate of flow insaid'trough being thus varied.

4. A structure as defined in claim 3, wherein the regulating meansincludes a pivotally mounted balance beam having a pair of arms, with aweight mounted on one arm and the other arm connected to said trough formovement of said balance beam thereby.

5. A structure as defined in claim 1, wherein said trough is connectedto said regulating means at a one end and to said further trough at theother end, this arrangement resulting in only the other end of saidtrough being displaced by said further trough and the rate of flow insaid trough being thus varied.

6. A structure as defined in claim 1, wherein the regulating meansincludes a pivotally mounted balance beam having a pair of arms, with aweight mounted on a one arm and. the other arm connected to said troughfor movement of said balance beam thereby.

1. An apparatus, comprising, in combination: a. means for making aquantitative measurement of a flow in a flow path, the measuring meanscontinuously making quantitative measurements of a flow portion divertedfrom the flow path, and including a displaceably mounted trough defininga flow channel connected to the regulating means and arranged forreceiving the diverted flow portion, and a further trough arranged toreceive from said trough at least a part of the diverted portion, saidfurther trough being displaceably mounted at the ends thereof andconnected to said trough at one end for displacing same; and b. meansfor regulating the impetus to the flow in the flow path as a function ofthe measurement made by the measuring means.
 2. A structure as definedin claim 1, wherein the troughs are connected together by a means forinversely duplicating in said trough a displacement of said furthertrough.
 3. A structure as defined in claim 2, wherein said trough isconnected to said regulating means at a one end and to said furthertrough at the other end, this arrangement resulting in only the otherend of said trough being displaced by said further trough and the rateof flow in said trough being thus varied.
 4. A structure as defined inclaim 3, wherein the regulating means includes a pivotally mountedbalance beam having a pair of arms, with a weight mounted on one arm andthe other arm connected to said trough for movement of said balance beamthereby.
 5. A structure as defined in claim 1, wherein said trough isconnected to said regulating means at a one end and to said furthertrough at the other end, this arrangement resulting in only the otherend of said trough being displaced by said further trough and the rateof flow in said trough being thus varied.
 6. A structure as defined inclaim 1, wherein the regulating means includes a pivotally mountedbalance beam having a pair of arms, with a weight mounted on a one armand the other arm connected to said trough for movement of said balancebeam thereby.